Conventional shooting game systems have drawbacks in that they are not realistic because games are played in a virtual environment produced by using computer graphics.
Thus, there have been made many attempts to remodel environment for the games by using the computer graphics for the purpose of enhancing reality thereof. These days, pictures of real environment have been partially used, which prove to make a game environment more realistic. Such a more realistic environment, however, is still different a lot from the real environment. Such disadvantage of the conventional shooting game systems is apparently brought out when compared with a case where a video of an actual event is utilized, effectively providing a more real-world-like game environment.